Apparatus for supplying liquid fuel to internal-combustion engines and for analogous purposes



Feb. 5, 1929. I 1,700,794

A. H. GIBSON APPARATUS FOR SUPPLYING LIQUIDFUEL TO INTERNAL COMBUSTIONENGINES AND FOR ANALOGOUS PURPOSES Filed Aug. 25, 1925 Patented Feb. 5,1929.

APPARATUS FOR SUPPLYING LIQUID FUEL TO INTERNAL-COMBUSTION ENGINES AND vFOR ANALOGOUS PURPOSES.,

Application filed August 25, 1925 Serial No. 52,476, and in GreatBritainseptember 11, 1924.

The invention hasreference, primarily, to apparatus for supplying liquidfuel to internal combustion engines, and particularly those of motorvehicles, of the class in which the fuel is drawn by suction from a mainsupply tank to an intermediate vessel or carburettor from which it issupplied for use.

Apparatus is known in which an air space, within a vessel forming partof a direct suction system, permits of a flow of fuel to an engineduring certain running conditions, but such apparatus does not providefor continuity of supply during changing load or acceleratingconditions, and for ample reserves of fuel for starting purposes.

If an air space in a vessel will only ensure a continuous flow of fuelduring certain running conditions of an engine, it cannot serve anyuseful purpose. In fact, a direct suction feed without any interveningair space would be more advantageous.

The present invention ensures a continuous flow of fuel to the engineduring changing load or accelerating conditions and the formation andmaintenance of ample reserves of fuel for starting purposes.

Theinvention is characterized in that in a conduit system between aspraying orifice or orifices or point or points of fuel delivery to theengine, and a supply tank having a vent open to atmosphere, there areincluded one or more stationary but elastic air breaks constituted invessels or enlargements forming part of the system, through or fromwhich vessels or enlargements a continuous supply of fuel is drawn,whilst the engine is running,

I solely by the suction exerted through the passage or passages by whichfuel is delivered to the engine, means being provided whereby,

bcfore'the fuel level in a reserve vessel can sink below the mouth ofthe outgoing duct or ducts, such a degree of attenuation is produced inthe air break as to cause inflow. of fuel to such vessel at a volumerate not less than that of the outflow therefrom.

The invention contemplates, and is principally designed for, themaintenance of a fuel supply from a storage tank disposed at asubstantially lower level than the intake I to the engine, but it can beapplied to cases where the storage tank is at the same level as or at ahigher level than the fuel intake to the engine.

is obvious that the invention may be utilized for supplying to theengine or its I parts liquids other thanfuel, such aslubrieating oil orwater. It is also obviousthat when two or'more different fuels, waterorother liquids are desired to mix in certain proportions at any pointforpoints in the conduit system, the desired proportions may be obtained bysuitably regulating the relative backward drags on the variousliquids atthe common point or junction of suction.

I The invention will be described with reference to the accompanyingdrawings which, illustrate diagrammatically several alternative types ofconstruction. Though for the purpose of illustration, only one fuel ductis shown leading to and from a reserve vessel, any number of ducts maybe provided, and one of them may supply fuel for idlin or slow runningof the engine.- may sub-divide into two or more branches. Any fuel ductmay lead from the top, sides or bottom of a reserve vessel,'provided theconditions required by the invention are obtained. .When a constructionis used in which, on stopping the engine, the fuel in may have two ormore compart- Fig. 1. is a diagrammatic illustration of one form of theinventiom'in which provision between a supply tank and the of deliveryto the engine.-

Figs. 2 and 3 are diagrammatic illustrapoint or points tions showingmodifications.

Referring to Fig. 1, a represents a main supply tank usuallypositionedatthe rear I v 1100 located on or adjacent to the instrumentboard. The tank a'h'a's a vent a open tothe of a motor vehicle, and b areserve vessel atmosphere, and the vessel Z) is assumed to be closed tothe atmosphere. A pipe dconnects I the tank a with vessel 6, anda pipe 6extending well down into the vessel Z2 connects the reserve vessel'maybe of mul- I 1s made for the creation of two fuel reserves,

Any fuel cuct that. immediately fuel commences to flow,

fromthe vessel Z) on restarting the engine, fuel immediately commencesto flow into the vessel to replace that withdrawn. 7

Assume the apparatus commencing to work for the first time after itsinstallation on a motor vehicle, the tank a containing a supply offueland the vessel Z) having been filled 'by hand with fuel up to alevel much above the mouth or inlet end of the pipe 6 but leaving an airspace represented by A, then the action of the apparatus is. as follows:

On engine suction being applied to the pipe 6, fuel is drawn from thevessel Z) through the pipe 6. The withdrawal of fuel causes the air inthe vessel 5 and the air in the ances in the pipe d.

. filling.

pipe d to becomeattenuated with the result that fuel rises to the vesselZ2 from the main supply tank a. The engine will now continue to run witha continuous unbroken supply of fuel so long as there is fuel in thetank a to supply the vessel 6. On stopping the engine, the valve 0 inthe pipe 6 closes automatically by the difference in pressures.

on its two sides, and in so closing traps negat1ve pressure in thevessel 6. The fuel level in the vessel 6 is now at a lower level thanwhen the vessel was first filled manually, but is still above the levelof the, mouth of pipe 6, and it will not fall below such mouth insubsequent runnings of the engine. The extent of rise and fall of thefuel level in the vessel band the degree of attenuation in the air spaceabove the fuel during changing load or changing speed of the engine willdepend on backward drag forces and resist- On restarting the engine fuelwill commence to flow through the pipe 6 as soon as the suction forceequals the trapped depression in vessel 5, after makallowance for anyhead or drag due to fuel trapped in pipe 2. The valve 6 may bepositioned at. any point in the pipe 6,

and the pipe itself may be connected to and extend downwardly from thelower part o the vessel Z), the trapped depression in th vesselpreventing, when the engine is stopper running, any leakage of fuel fromthe vessel. suitable provision being made to prevent fuel flowing fromthe vessel during manual Thepform of apparatus as thus far dethe engineis stopped running, owing to the presence of foreign matter in the fuel.

Provision is made to ensure that whilst the engine is running the airpressure in any fuel reserve vessel is quickly adjusted to a degreesufficient to draw fuel to such vessel at required changing rates ofinflow without. any great change taking place in the level of the fuelin the vessel such as might uncover tne mouth of the main fuel duct.This'provision may take several forms. As shown in Figs. 1 and 2, ittakes the form of an air absorbing hole or passage in the pipe throughwhich fuel flows from the reserve vessel. in 1 the pipe 6 proceedsupwardly from the vessel Z), but it has in it a small hole eh positionedwell above the bottom mouth or lower end of the pipe. It is essentialthat this hole be very small as compared with the bore of the pipe 0, toensure that when the hole is uncovered fuel shall continue to risethrough the bottom tom mouth of the pipe 0, any tendency for V the fuellevel to fall materially below the hole eh is quickly arrested by smallqua ntities of air being drawn through such hole and mixing with thefuel passing through pipe 0. The rapid increase in negative pressure inthe space A due to the extraction of air in the manner just describedaccelerates inflow of fuel to the reserve vessel, and as soon as thefuel level has again covered the hole eh, furtherabsorption of airthrough such hole ceases until the hole is again uncovered. The airabsorbing hole may if desired, be inthe form of a small mouth to abranch pipe joining up, inside or outside the vessel '7 to the pipe 6 orit may, take the formof a very narrow slit. More than one air absorbinghole may be employed if desired. When an air absorbing hole or pas--sage is covered by fuel it is obvious that fuel will be absorbed throughit instead of air.

In Fig. 2 the pipe '6 extends upwardly into the vessel 6. In thisconstruction it is essential that the bottom hole or passage cm, whichacts in this case as the main fuel mouth in the pipe e, should be smallin order that some of the suction transmitted through thepipe e may befelt at its top mouth in order to maintain the fuel level at or near thelevel of such mouth by absorption of small quantities of air through themouth when not covered by-fuel. A valve such as 0 Fig. 1, may also beused in this last described construction.

In constructions embodying the air absorption principle, such asillustrated by Figs."

vided with a suction opened valve similar to the valve 6 It is thuspossible to employ a series of the vessels in the conduit, but same maynot be desired in some instances, and so far as the apparatus shown inFig. 1 is concerned, the pipe 6 may communicate directly with the engineat a point of liquid delivery which is under sub-atmospheric pressure.Fig. 1' also shows a check valved in the pipe d to prevent reverse flow.

If the main supply tank be positioned above the level of the deliverypoint or points to the intake of the engine, the air break or spaceabove referred to can still be made to perform its required functions,but in order that siphonic flow may not take place when the engine isstopped it is preferable that the air break should extend froma'position materially above the level of the fuel in the maintank to aposition very near to the level of the fuel intake to the engine. If theair break commences from a position about the level of the bottom of themain supply tank, it desirable that it should extend to a position wellbelow the level of the fuel intake to theengine. A long air breakprevents si'phonic flow by breaking up a drag fall due to molecular at-'traction. The construction adopted and the positioning and dimensions ofthe air break not only determine whether there will be any siphonictendency or not when the engine is stopped, but also the degree of airor vapor pressure in the air break space. Some constructions give riseto negative pressure in the air break and others to positive pressure,when the engine is running, and the degree of pressure varies with theforces to be overcome in drawing fuel at the required rate from the mainsupply tank. Where positive pressure is existent in an air break whenthe engine is not running, depression, when-the engine is running, mayor may not cause such pressure to change over to a negative state. Inother words, the positive pressure of an air break may be subject to acertain depression and yet remain in a position state, but of lesser orreduced degree. When no regard is given to the positioning of the airbreak, it may be necessary to safeguard against siphonic action, whenthe engine 1S stopped, by placing in the fuel circuit a lift resistance,the resisting etfectof which increases with increasing downwardgradients, or to stop siphonic flow action by the admission of air at anappro priate point provided'the admission of such a1r 'will'not'releasea trapped depression in a reserve vessel. The employment of a' lift re?sistance is'equivalent to disposing the main tank at a level below thepoint or points of fuel delivery to the intake to the engine.

Fig. 3 illustrates one type'cf construction to prevent siphonic fiowaction when the .en-

gine is stopped running in acase where the supply tank, as abovementioned, is situated above the level of the fuel delivery to theintake of the engine.

To-compensate, wholly or partly, for variation in fuel lift or fuel headwhen a motor vehicle is proceeding uphill or downhill, there may beemployed in the circuit a resistance'or resistances arranged to increaseor decrease in effectaccording to the inclination of the vehicle fromthe horizontal. Such a resistance may comprise one or more metal balls51', as seen in Figs. 1 and 2, or a weighted flap or needle valvesubject to the action of gravity and which will operatev automatically.If preferred, however, a manually-operable 1'ssistance or resistancesmaybe employed. The balls or other gravity corrective resistance are soarranged that when the vehicle is travelling on inclines so as to raiseor. lower the main supply tank with reference to the de{ livery point offuel, such resistance will be 1 increased or decreased inproportion.Thus,v when the supply tank is? raisedwith reference to the point offuel delivery the balls or other means may bemovedjtoward avertic'alposition in order to increase the gravity effect and resistance thereof,and vice versa.-

According to the position and resistlng effeet of the above named or anyother resistance in the fuelconduit, so will'an'enclosed air spacepermit of different degrees of acceleration of an engine. g i

A valve such as 6 Fig. .1, may be employed in any construction adopted,and when two or more fuel pipes lead from a reserve vessel, or a fuelpipe connects to the fuel intake of the engine by two or more branchpipes, such a valvemay be provided in eachor any pipe or branch toensure a continuous flow of fuel to the engine whilst it is runningnotwithstanding that one or more of the pipes or A controlling cook orcocks or other means to regulate the rate of fuel flow may be providedat any convenient point in the system.

The flow of fuel may be partly regulated by the admission of air to theconduit either. at

-or near the highest point in the conduit or between that point and thepoint of fuel delivery to the engine, and the admission of."

such air may be made variable and dependent upon movement of the enginethrottle or throttles. vAir may not, however, be admitted to or before areserve vessel except in the case of constructions of the type billustrated Although the use or" floats in afuel feed system is to beavoided where possible, a float may be used, in any construction inwhich it may be found advantageous.

The invention obviates necessity for the use of a separate non-fuelconveying suction pipe connected to the induction system of an enine forthe purpose of raising fuel from a aw level supply tank. If such aseparate suction pipe were added to apparatus according to the inventionit would afiord noadvantage.

Having thus described my invention, what I claim asnew and desire tosecure by Letters Patent is a i 1. A liquid supply apparatus for aninternal combustion engine comprising a liquid supply tank having an airentry vent, a liquid conduit leading from the tank to a point of liquiddelivery which is under sub-atmospheric pressure so that thesub-atmospheric pressure extends into said conduit, said coni V duithaving a liquid reserve vessel therein through which the liquid flows,said vessel having a liquid inlet and a liquid outlet and an air spaceabove the liquid outlet, in order that said air space will permit ofattenuation of the air therein when the liquid is drawn by saidsub-atmospheric pressure from the Vessel so that said air attenuationwill draw 7 through which the liquid flows, said vessel having a liquidinlet and a liquid outlet and an air space above the liquid outlet, inorder that said air space will permit of attenuation of the air thereinwhen the liquid is drawn by c said sub-atmospheric pressure from thevessel 7 so that said air attenuation will draw'liquid into the vessel.from said tank, the portion of said conduit leadingtrom said vessel hav-I mg a restricted air hole in said vessel at a higher level than theliquid outlet to permit air to be Withdrawn from the vessel before theliquid level therein fallsto said liquid outlet.

3. A liquid supply apparatus for an internal combustion enginecomprising a liquid supply tank having an air entry vent, a liquidconduit leading from the tank to a point of liquid delivery which isunder sub-atmospheric pressureso that the sub-atmospheric pressureextends into said conduit, said conv duit having a liquid reserve vesseltherein through which the liquid flows, said vessel having a liquidinlet and aliquid outlet and an air space above the liquid outlet, inorder that said air space will permit 01": attenuation of the airtherein when the liquid is drawn by said sub-atmospheric pressure fromthe vessel so that said air attenuation will draw liquid into the vesselfrom said tank, said liquid inlet and outlet of the vessel being athigher and lower levels than said tank. g

4:. A liquid supply apparatus for an internal combustion enginecomprising a liquid supply tank having an air entry vent, a liquidconduit leading from thetank to a point of liquid delivery which isunder sub-atmospheric pressure so that thesub-atmospheric pressureextends into said conduit, said conduit having a liquid reserve vesseltherein through which the liquid flows, said vessel having a liquidinlet and a liquid outlet and an air space above the liquid outlet, inorder In testimony whereofI my signature.

ALFRED HERBERT GIBSON.

